5 letter words:
boost7,
boots7,
bouts7,
4 letter words:
boos6,
boot6,
bots6,
bout6,
bust6,
buts6,
stob6,
stub6,
tubs6,
oots4,
oust4,
outs4,
soot4,
3 letter words:
boo5,
bos5,
bot5,
bus5,
but5,
sob5,
sub5,
tub5,
oot3,
out3,
sot3,
sou3,
too3,
uts3,
2 letter words:
bo4,
os2,
so2,
to2,
us2,
ut2,